hydrofoil?

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dansoph

Petty Officer 3rd Class
Joined
Oct 30, 2002
Messages
86
does anyone have an opinion about these things you bolt on to your lower unit ( mine is a 1998 90 evenrude )? when i pull skiers or tubeing, the motor doesn't seem to have the hole shot power it used to have. i have top end power but the take off isn't what it used to be. thanks for any info. the boat is a 17' br.
 
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cobra 3.0

Lieutenant Commander
Joined
Jul 31, 2003
Messages
1,797
Re: hydrofoil?

I have a Stingray hydrofoil and love it for skiing! My bowrider planes in 1/3 the time with great hole shot! It also renders the boat flatter and more stable in turns. Your top end will suffer 2-3 mph, but no biggy!
 
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Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: hydrofoil?

I think I'd try and figger out where the engine's power went before adding something new. That's just me though. ;) <br /><br />c/6<br />Hooty
 
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Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: hydrofoil?

I agree Hooty. dansoph, lets look at this as a map. We gotta know where we're at now to figure out the best way to get where we wanna be. <br /><br />Tell us about your set up. What kind of rpm's are possible now? What was possible before? Whats the compression? When was the last de-carb job? Carbs clean, etc?<br /><br />The fin is a tool. With the proper fin and set up you should gain holeshot as well as top speed. With the addition of a fin your set up will have to be adjusted slightly. <br /><br />Good luck!
 
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steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: hydrofoil?

The hydro foil is a great aid but where did the power go?Have you shifted weight to the rear?<br /> Has the boat picked up weight somewhere?A leak<br />or if glass is it absorbing water?<br />Has the motor trim changed?Usually should be trimmed in all the way to get the best hole shot.
 
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Cricket Too

Lieutenant Commander
Joined
May 14, 2003
Messages
1,732
Re: hydrofoil?

I have an old SportCraft that absorbed water in the flotation and made it heavier in the stern, I couldn't get it on plane with my 70hp and didn't want to replace the flotation as it is an old boat and used for just running around the bay and working on the water. I installed a fin on my lower unit and instantly was able to get it on plane and have a better hole shot. So I would try to figure out where your power went and then either fix it if possible and if not feasable I would reccomend the fin. Good Luck.
 
rickdb1boat

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: hydrofoil?

I'd still put the foil on, but do find the source of the loss of power. Those foils sure do help getting on plane! Is it just a little power loss or does it really feel like it's dragging more than normal? Decarb, new plugs may solve the problem if it's just a little slugggish. If worse, first check compression in all cylinders to make sure your engine is up to par. Then go from there. Let us know what you find...
 
waterinthefuel

waterinthefuel

Commander
Joined
Nov 15, 2003
Messages
2,726
Re: hydrofoil?

I put a Stingray on my 28hp Johnson 13 foot fiberglass boat and my top speed increased by almost 5 mph, as well as my boat planing over at half the speed it used to. I have seen the performace of 4 boats before and after the Stingray, and every single boat performed better, with top speeds increasing because you could trim the engine up higher, thus reducing the amount of boat in the water and drag created.
 
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walleyehed

Admiral
Joined
Jun 29, 2003
Messages
6,767
Re: hydrofoil?

My 2 cents....I think in your situation the foil would be a band-aid fix. You need to find out what the reason is for the loss of power..
 
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dansoph

Petty Officer 3rd Class
Joined
Oct 30, 2002
Messages
86
Re: hydrofoil?

thanks for the replys. it's on a 1998 sunbird bow rider 17'.it's not really BAD, but people ( adult's ) who used to pop out of the water, are now struggling to get up on skies. and no it's not that wer'eolder or fatter!ive 'e used the trim to help lately. i think new plugs and decarb is the cheaper solution to start. thanks again
 
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cobra 3.0

Lieutenant Commander
Joined
Jul 31, 2003
Messages
1,797
Re: hydrofoil?

I hope you are running 89 octane or higher? Running regular octane gas eventually causes trouble( at least on my 1986 3.0 it does). Have you changed props or is the prop banged up? Certainly new plugs and maybe a new gas filter can't do any harm either. Also, cleaning the air intake system as well is a good idea.
 
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dansoph

Petty Officer 3rd Class
Joined
Oct 30, 2002
Messages
86
Re: hydrofoil?

cobra 3.0 does my motor have an air filter of some kind? i use regular gas and the prop is the one that came with the motor from the factory.
 
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DJ

Guest
Re: hydrofoil?

dansoph,<br /><br />No, your engine does not have an air filter, The housing on the front of the engine is just actually a silincer.<br /><br />You DO NOT need premium fuel. Actually, it is detrimental to an outboard. Premium fuels burn cooler, leading to deposits in the combustion chambers. Those deposits cause all kinds of problems, from sticking rings to glowing embers which cause detonation. Stick with the 87 octane.<br /><br />When you replace the plugs, make sure you use Champions. OMC's do not like any other plugs-for some reason.<br /><br />Also, what is your wide open throttle rpm? It should be at least 5500.<br /><br />What shape is your prop in?
 
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cobra 3.0

Lieutenant Commander
Joined
Jul 31, 2003
Messages
1,797
Re: hydrofoil?

...sorry I was thinking inboard with the fuel recommendation :eek:
 
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